Dandy roll construction



Oct. 3l, l1933.

J. A. `SPENCER 1,933,154

DANDY ROLL CONSTRUCTION Filed Aug. 25, 1932 /f 3. mlm/f @47 k'/f ma INVENTOR A TTORNEY Patented Oct. 31, 1933 UNITED ,STATES PATENT oFFlcE 2 Claims.

This invention relates to improvements in the construction of dandy rolls for paper making machinery. A dandy roll is an open framed roll covered with wire cloth and positioned to press upon the upper surface of the paper web while the latter is being carried upon the Fourdrinier wire. It has been known for years that with certain paper stocks the framework of the dandy roll (usu ally a wire helix directly supporting the wire cloth and itself carried by an inner frame) would in some Way act through the wire cloth and leave an impression upon the web which would persist through the various iinishing processes. The cause of this action has been obscure and no remedy has hitherto been proposed.

I have found that the cause is apparently twofold. In the rst place, I believe that the, socalled winding wires which form the outer portion of the roll framework tend to shift into the spaces between the iine wires forming the wire cloth, plugging up the meshes. This action is accentuated in use by the packing of small iibers into the pockets formed between the sides of the winding wires and the Wire cloth. This results iin an uneven effect on the paper in bands across the width of the web corresponding to the spacing of the winding wires. The second cause of the marking of the web by the winding wires I believe to be the difference in rigidity of the wire cloth at points where it rests upon the winding wires and at points between them. This of course varies the compacting effect of the dandy roll along bands similar to those mentioned above.

By my invention, both of these causes of trouible are removed with but slight change in the standard roll construction. The open framework of wire which supported the covering in former rolls can be, if desired, left substantially unchanged; the only alteration being in the contact jbetween the framework and the wire cloth cover.

In former rolls this contact was continuous around the helical perimeter of the winding wire which formed the cylindrical exterior boundary of the frame. According to my invention this contact is made discontinuous both longitudinally and circumferentially of the frame; and is preferably obtained through spaced prominences, such as the successive outwardly facing portions of a helical rib cut or rolled upon the wire.

The invention will now be described in connection with the accompanying drawing, in which:

Fig. 1 is a side elevation of a dandy roll embodying my invention with the wire covering cloth and the winding wires successively broken .'iaway to disclose the internal structure; and

Figs. 2 to 6 inclusive are enlarged views showing several modified forms of the winding wires on an enlarged scale.

The dandy roll is supported on any desired main framework. As shown, the roll is provided with end pieces 10 having the usual projecting pivot bearings 11. Between the frames extend rods or wires 12, to which are soldered or otherwise secured an internal helical coil 13. A rigid frame is thus provided upon which can be mounted the actual support for the wire cloth. For this purpose the longitudinal wires 12 are preferably grooved or nicked at 14 along a helical path to furnish a spacing guide for what is known in the trade as the Winding wire 15. Successive turns of this helically wound wire form parallel circumferentially extendingsupports upon Which the wire cloth covering 16 is carried. The winding wire may be soldered in place upon the rods 12.

As thus far described the roll may be considered as of standard construction. My invention consists in decreasing the area of contact between the winding Wires and the wire cloth, and at the same time making the reduced lines of contact between them extend at an angle to the wires forming the covering 16. This may be accomplished in several ways, but preferably by grooving or ribbing the winding wires 15 prior to their being wound on the internal frame. Several forms of wire have been shown in Figs. 2 to 5 of the drawing, all but that shown in Fig. 3 having the ribs or grooves helical so that they reduce the area of contact and also cause it to extend diagonally of the cover.

The various forms shown are intended as i1- lustrative only, any type of rib formed on the Wire which accomplishes the results set out above being suitable. In Fig. 2 I have shown the winding wire 15 as provided with a double-threaded rib 20 of sinuate profile. Fig. 5 shows a similar form of rib 21 made in single-threaded form. Fig. 4 shows a single-threaded rib 22 rising somewhat more abruptly from the cylindrical body of the wire. The form shown in Fig. 4 may be cut from a solid wire if desired, but it is preferable to use a plain wire l5 and wrap a smaller wire helically around it to form the rib 22. This smaller wire may be solderedin place, or it may be left `unsoldered, the roughness of the wire cloth holding it in place. In all of these forms the contacting portions of the ribs extend obliquely, making a substantial angle with respect both to the warp and weft vof the wire cloth cover. In Fig. 3 the ribs run circumferentially of the ln the same manner as the ribs of the other modi# cations. It will be understood from the above discussion that the invention may be carried into practice in various specific forms, and I have therefore pointed out its novel features both broadly and specifically in the following claims.

sus

coo Y What I claim is:

-1. A dandy roll comprising a frame having a cylindrical exterior boundary formed by a wire member twisted to form a helical rib, and a cylindrical cover of wire cloth surrounding the frame and supported by the spaced outwardly facing helical edges of said twisted wire.

2. A dandy roll comprising an internal frame, a wire -wound helically about the inner frame, said wire being composed of at least two wires twisted together so as to present a helical rib, and a cylindrical cover of wire cloth surrounding the frame and supported by the spaced outwardly facing portions of said helical rib.

JOHN A. SPENCER. 

